1. Field of the Invention
This invention pertains to the field of measurement and testing. More particularly, the invention pertains to measurement of the gas content of material.
2. Description of the Prior Art
In the formation of a thin film of a desired material it is frequently necessary that a specific substance be present during deposition of the film to produce the material. When the film is brought to different conditions than those at which the film was deposited, this substance escapes from the film before the film can be analyzed for the substance. As a result, it is not only difficult to determine that the substance was present in the film during deposition thereof, but it may be impossible to determine that the presence of such a substance is required to produce the desired film material. While it is conceptually possible to analyze a film for such a substance during deposition of the film, the fact that the deposition typically occurs from evaporation in a vacuum chamber renders this concept impractical since the necessary apparatus, unless of complex and presently non-existing construction, would be damaged by deposition on the apparatus or would not function under the conditions for deposition. As a result, it is necessary to transfer the deposited film and substrate through an environment sufficiently close to the usual ambient temperature and atmosphere that heretofore the substance escaped from the film or was replaced by a greater or lesser quantity of the substance present in the transfer environment.
More specifically, in the depos1tion of a thin layer of a well-known niobium/germanium compound, Nb.sub.3 Ge, where this compound is to have a desired structure which results in the layer becoming superconducting at a relatively high temperature, it has been found necessary that the deposition occur at about 900.degree. C. and with oxygen present in the layer during deposition so that the desired structure is formed instead of some other niobium/germanium structure on. However, when the layer has cooled to about 500.degree. C., the oxygen has diffused from the layer so that analysis thereof for oxygen would be useless insofar as determining the presence of oxygen during the actual deposition conditions.